[sdiy] F2V with PIC or AVR?

[David G. Dixon]

> The really tough part is to condition the signal so that you 
> can get ONLY the fundamental frequency.

So, what are the steps one must take to isolate the fundamental?  I'm
assuming some or all of the following: AC coupling (to centre the signal
about ground), LP filtering (to remove extraneous wiggles which might cross
zero but not represent the fundamental, such as HF resonance), and
comparating with hysteresis (to generate a clean square wave).  The LP
filter could even be tuned to the derived frequency plus a discrete distance
(like an FBI agent on your tail).

> Pitch-to-Voltage is the easy part.  Most of the signal 
> processing involves figuring out when a note begins, when it 
> ends, and when you can no longer trust the input to be valid 
> (enter hold mode etc.)

So, in other words, envelope following.  Is there a lot more to it that
that?  Is the EF best done on the raw signal or the filtered signal?

> The PV-1 will not work (correctly) unless you have a good 
> input signal.